A current lawsuit wants to allow health insurers to deny coverage to anyone with a preexisting condition—and the case has the backing of the Trump Administration. As The New York Times reports, the Justice Department said it would no longer defend provisions of the Affordable Care Act (aka Obamacare) that protect people with preexisting conditions, which is the topic of the lawsuit.

How is this lawsuit even possible? In case you’ve forgotten, Obamacare is already the law of the land, and it prevents discrimination based on clients’ health status. What’s more, the Justice Department traditionally supports federal laws.

Here’s what’s going on.

The court case was filed by Texas and 19 other conservative states. As Vox explains the issue, the case is built on the legal concept of “severability.” The basic idea is that if one aspect of a law has been struck down, then it stands to reason that the entire law is unconstitutional.

In this case, part of Obamacare has effectively been struck down. That happened when Republicans passed a tax bill last year that eliminated the fine for Americans who don’t have health insurance, basically ending the individual mandate to have insurance.

The Texas case argues that the mandate was such an important aspect of Obamacare that without it, the entire law is unconstitutional, including the stipulation that insurers can’t deny coverage or charge higher rates to people with preexisting conditions.

Legal experts told Vox that the Texas argument is “ludicrous” and “absurd,” namely because when Congress passed the tax law that ended the individual mandate, legislators clearly felt it was OK to leave in the other provisions, such as protections for people with preexisting conditions.

Although the case may seem like a long shot, Vox notes that Texas filed the case in a conservative federal district court, so it very well might move forward. Regardless, a ruling could take months.